Apparatus for dressing wheels of grinding machines



Oct. 31, 1944. c, E wALLlNG 4 2,361,724

APPARATUS FOR DRESSING WHEELS OF GRINDING MACHINES Filed Nov. 7, 1940 INVENTQR. L'LYUE f. WflLL/NG Patented Oct. 31, 1944 ENT. 5 OFFICE APPARATUS FORDRESSING WHEELS OF GRINDIN MACHINES Clyde E. Walling, Cleveland, Ohio Application November 7, 1940, Serial No. 364,648 3 Claims. (01425-41) This invention relates to a 'method of and apparatus for dressing wheels of grinding machines, such as used for sharpening milling cutters, hobs, reamers, taps and so forth. Grinding machines of this type generally include vertically rotatable grinding wheels adapted to be swung around a vertical axis, and adjustably mounted tool dressers permitting of proper shaping, forming and truing of the grinding wheels. As well-known, wheel dressing operations for grinding machines, particularly, dressing of a wheel for true circular relief grinding on reamers, taps and cutters, must be effected so that the dressing tool passes across the wheel at a right angle to the center line of the tool to be ground, otherwise grinding opera tions might injure the cutting edge of the tool, or even effect a complete destruction of such a cutting edge. The above defined requirement for dressing a wheel together with the customary re-, quirement that a grinding wheel should rotate about an axis substantially parallel to the surface to be ground will prevent the use of the full width of a wheel, unless such wheel exactly fits the 15 1 t be ground, and makes it necessary to have at hand a large number of grinding wheels of different widths so as to avoid excessive waste of wheel material.

It is the primary object of the, present invention to provide an improved method for wheel dressing, which method permits the dressing tool to pass across a wheel at a right angle to the center line of the tool to be ground, even though the axis of rotation of the wheel is arranged obliquely to the surface to be ground while simultaneously shaping substantially the entire peripheral surface of the wheel in spite of excessive Width for a particular job, all for the purpose oi. eliminating excessive waste of wheel material and effecting proper and eflicient grinding operations.

This general object of the invention is attained by turning the axis of the wheel in a horizontal plane to any desired angle with respect to the center line of the tool to be ground and thereafter setting the dressing tool at a right angle to the center line of the tool to be ground, so that the wheel will be dressed to the true curve of such a tool. The procedure of setting a grinding wheel angular and not rectangular with re spect to the center line of a tool to be ground permits of the use of the entire peripheral surface of a grinding wheel for grinding operations without special consideration of the size of a cutting a groove in the grinding wheel and grinding imperfect circular relief on a tool. 7 Another object of the invention is to provide a machine for grinding tools, such a machine including in combination a horizontally disposed wheel supporting spindle journaled in a vertically rotatable head, with a horizontally and vertically pivotally mounted dressing tool permitting of setting of the wheel of the grinding machine at any desired angle with respect to the center line of a tool mounted on the machine and setting of the dressing tool at a rght angle to the center line of the mounted tool.

Still other objects and advantages of the invention will be indicated in the following description of an exemplified form of a grinding machineembodying the invention and'are rendered apparent therefrom in connection with the annexed drawing depicting a preferred typical tool tool, and, in addition, eliminates the danger of grinding machine.

In the drawing: 7 Figure 1 is afragmentary side elevation of a tool grinding machine constructed in accordance with the invention and adapted to operate in accordance with the grinding method disclosed herein. Q

Figure 2 is a plan ,view of a tool dresser mounted in a bracket for pivotal support on inters'ecting vertical and horizontal axes, the figure showing in addition in dotted lines the rectangular relation of the thus mounted dressing tool to the center line of a tool to be ground and the angular, not rectangular relation of the.

grinding wheel to such a center line.

Figure 3 is a side view of Figure 2 showing the same relation between the dressing tool, the grinding wheel and the center line of the tool to be ground.

Figure 4 is a perspective view of the dressing tool longitudinally shiftably mounted in a base, which base is rotatably supported in the tool dresser bracket.

Referring now to the exemplified form of the invention reference numeral 2 denotes a grinding machine embodying a suitably constructed stand 3, which stand vertically adjustably supports a bed 4. This bed is vertically shiftably mounted on stand 3 by means of a threaded shaft 5 and gearing 6, and mounts a slide! carrying a pair of lengthwise adjustable centers 8 and 9 for axial support of a tool. Stand 3 also mounts a grinding wheel l0 secured to a spindle l I in a head I 2, which head is vertically rotatably secured to stand 3. A scale I 4 on stand 3 cooperates with a mark [5 on head [2 and permits of proper setting of the wheel supporting head [2 with respect to the tool to be ground. Head [2, in addition mounts a bracket H; which, adjustably carries a specific wheel dressing device [1. This device permits the wheel dressing tool I8 carried thereby to be set at any horizontal angle with respect to the grinding wheel l0, and embodies a bracket member 19' and a tool supporting member 20. The bracket member [9 consists of a slitted ring-shaped bearing 2| with perforated flanges 22 permitting of contraction of said hearing by a screw member 23 threaded through said flanges,

and a slotted supporting arm 24 longitudinally adjustably securing said bracket member to bracket porting member 20 is formed as a cylindrically shaped block, the upper enlarged'portion 25=of which rests on a circular shoulder 26 of bearing 7 2|. Member 20 pivotally mounts crosswise thereof a short shaft 21 which carries shiftably in a bore 28., arranged at a right angle to the axis of said shaft, the graduated dressing tool l8, the latter being held in its set position by a set screw 29 It will now be seen that the tool supporting member 20 can be freely rotated in its ringshaped bearing 2| and thus be set to any desired horizontal angle in said. bearing, such setting being facilitated by a scale 29 on bearing 2| and a mark 30 on member20. f

To properly dress the wheel of a tool grinding machine with the structure described above, head I2 is vertically rotated so that wheel [0 and bracket I6 with wheel dressing device l'l are shifted from position A (see Fig. 2, full lines) to position B (see Fig. 2, dash-dotted lines) This rotation of head I2 shifts wheel l0 and wheel dressingdevice I! so that wheel 10 and dressing device l'l' form with the center line (b) of the tool to be ground an angle (a) which is the angle under which wheel 10 in grinding operations approaches the tool. dressing device I! in this latter position of wheel [0 and dressing device I! is unsatisfactory, as dressing tool I8 willipass across wheel 10 at an oblique angle, not at a right angle to the center l6 on head [2. The tool sup Dressing of wheel [0 by tion opposite to the direction of rotation of head l2 an angular extent (a), so that dressing tool l8 during dressing operations passes across wheel ID at a right angle to the center line of the tool to be ground.

The above described method permits the use of the entire width of a wheel for grinding purposes without considering the width of the wheel with respect .to the size of the tool to be ground, furthermore eliminates excessive waste of wheel material, and finally prevents imperfect grinding due to high particles in the peripheral surface of :adressed wheel.

claim is:

1. In a tool grinding machine with a horizontally rotatable supporting head a grinding wheel vertically rotatably supported by said head, a

line of the tool to be ground. This undesirable condition is overcome by moving tool supporting member 20 in wheel dressing device I! backwards the angular extent of rotation of head l2, that is moving said member in a direcdressing tool supporting device having axially rotatable tool supporting means and supported onsaid head, and a dressing tool pivotally mounted in said supporting means in axial alignment with respect thereto, said dressing tool supporting device permitting oscillation of said dressing tool crosswise of said grinding wheel and rotation ofthe plane of oscillation of said dressing tool by axial rotation of said tool supporting means without change in the relation of the axis of said dressing tool with respect to the axis of said grinding wheel in any adjusted position of said supporting head.

2. A tool grinding machine as described in claim 1, wherein said dressing tool supporting device includes a ring-shaped split bearing, wherein said tool supporting means consists of a cylin' drical block horizontally rotatably mounted in said bearingand wherein means are provided to lock said block in its rotatably adjusted position.

3. A tool grinding machine as described in claim '1, wherein said dressing tool supporting device includes a horizontally arranged, ringshaped bearing, wherein said tool supporting means consists of a ring-shaped member axially rotatably mounted in said bearing, wherein said ring-shaped member pivotally supports a shaft diametrically thereof, and wherein the said dress ing tool is adjustably supported in a bore aligned with the axes of said bearing and said ringshaped member.

' A CLYDE E. WALLING. 

